The present invention relates to underwater breathing methods and apparatus. More particularly the invention pertains to a safety supply valve method and apparatus for an underwater breathing system.
Although references may be found to "divers" as early in history as Homer's "Illiad" commercial diving activity, in significant part, was only recently ushered into existence through exigencies connected with offshore petroleum exploration and production.
In the offshore commercial diving industry safety is a paramount concern. In this regard the diving community is continually striving to develop equipment and operating procedures which will enhance diver safety. The subject method and apparatus invention is believed to be a notable step in this direction.
As previously mentioned, commercial diving activity was manifoldly expanded with the emergence of offshore oil and gas exploration and production in the fifties. In this connection divers are needed in the offshore oil industry for inspection tasks, making submerged connections, etc.
As the world's rate of demand for petroleum caught and then exceeded the rate of discovering land based oil supplies, it became economical to extend exploration and production activity into offshore regions. As an example, significant exploration, drilling and production activity presently exists in the North Sea which has an average depth of three to four hundred feet. At such depths considerable attention has been given to utilize gas mixtures which are compounded to minimize interference with normal absorption of oxygen by the bloodstream. Notwithstanding, however, use of sophisticated gas mixtures, at least some instances have occurred wherein a submerged diver has become confused or disoriented due to a lack of oxygen supply to the brain. To accommodate anomalous instances conventional diving helmets are typically fitted with a variable flow supply valve which is subject to diver control. In this regard if a diver occasions a sense of exhaustion, muscle fatigue, etc. all that is normally required is for a diver to open the supply valve in order to increase gas flow rates and thus oxygen to his system.
In at least some instances, however, it is possible that a diver may become disoriented due to oxygen starvation and actually turn down or close off the supply valve erroneously thinking that gas flow was being increased. It will readily be realized that such an occurrence would exponentially compound a diver's oxygen deficiency situation leading to possible unconciousness and in some instances even death.
Accordingly, it would be highly desirable to provide an underwater breathing system supply valve which would be fully operative under nominal conditions and which would also eliminate the possibility of a diver terminating his own gas flow.
Further under nominal operational circumstances it is highly unlikely that a diver's umbilical, or gas supply line, would lose pressure. Notwithstanding, however, the statistical improbability of such an occurrence it may be possible to visualize bizarre circumstances wherein a supply line may be severed or accidentally ruptured. In such circumstances it is necessary to prevent a counter flow of gas from the diver's pressurized helmet in order to preserve in the diver's helmet a gas bubble which will permit a safe return to the surface or an underwater working chamber.
Accordingly it would also be highly desirable to provide an underwater breathing system supply valve which would be fully operative under nominal conditions while eliminating the possibility of a diver erroneously terminating his own gas flow and further which would prevent a counter flow of gas from a diver's helmet in the event a supply line is accidentally ruptured.
The problems suggested in the proceeding are not intended to be exclusive but rather are among many which may tend to reduce the effectiveness of prior underwater breathing systems. Other noteworthy problems may also exist, however, those presented above should be sufficient to demonstrate that underwater breathing system supply valves appearing in the prior art have not been altogether satisfactory.